Fuel Charging and Controls

FUEL CHARGING AND CONTROLS

The fuel charging and controls system consists of the:
- electronic throttle body.
- fuel injectors.
- fuel charging wiring.
- fuel supply manifold.
- fuel pressure sensor
- fuel pressure relief (Schrader) valve.

The fuel charging and controls system is:
- a sequential multiport fuel injection (SFI) system.
- pulse-width modulated.
- mass airflow-controlled.

The powertrain control module (PCM) controls the fuel injection system. Injector pulse-width is varied to control the amount of fuel flow. Varying fuel pump output controls fuel pressure. The PCM commands the fuel pump driver module, which directly controls the fuel pump. The throttle body is electronically controlled by the engine management system (EMS). Throttle plate angle is changed electronically in response to throttle pedal movements initiated by the driver.







The fuel supply manifold:
- delivers fuel to the individual fuel injectors.
- receives fuel from the fuel supply line.
- is serviced as a lower intake manifold assembly only.







The electronic throttle body:
- controls air supply to the upper intake manifold by electronically positioning the throttle plate.
- is not adjustable.
- must not be cleaned.
- is serviced as an complete assembly only.

The fuel pressure relief valve:
- is used as a test port and to release fuel pressure.

The fuel injectors:
- are electronically controlled by the powertrain control module (PCM).
- atomize the fuel as the fuel is delivered.
- are deposit resistant.
- have an internal solenoid that opens a needle valve to inject fuel into the lower intake manifold.

The fuel pressure sensor:
- maintains constant fuel pressure to the fuel injectors and throughout the fuel system.
- is spring-loaded and operated by intake manifold vacuum.